ABSTRACT

Tropical soda apple (Solanum viarum), first detected in Australia in 2010, is a weed of agricultural significance as it reduces cattle stocking rates and limits stock movement. Gratiana boliviana (Coleoptera: Chrysomelidae) is an approved biological control agent for S. viarum in the United States of America (USA). Although the host specificity of G. boliviana has been extensively tested in the USA, additional no-choice tests were conducted to determine if the beetle is sufficiently host specific for release in Australia. The host test list included Solanum species native to Australia, as well as agriculturally important species that had been tested previously. Both adult and larval no-choice tests indicate that G. boliviana does not perform equally well across the target weed S. viarum and the other plant species included in the tests. Oviposition was observed on only two plant species besides the target weed, with significantly more eggs laid on S. viarum (19.5 ± 0.4 eggs/plant), followed by S. brownii (2 ± 0.4 eggs/plant) and S. melongena (1.8 ± 1.5 eggs/plant). Ninety per cent of eggs laid on S. viarum developed to adults, whereas only one egg laid on S. melongena completed development. Larval no-choice feeding assessments indicate that larval survival and development is highest on S. viarum (80%) followed by S. brownii (30%) and S. melongena (20%) and to a much lesser extent on S. lithophilum (2.5%). Our results contribute to the evaluation of the risk of potential off-target effects by G. boliviana feeding and development on native Australian or agriculturally important Solanum species.

摘要

热带苏打苹果 ( Solanum viarum ) 于 2010 年在澳大利亚首次发现，是一种具有农业意义的杂草，因为它降低了牛的放养率并限制了牲畜的流动。Gratiana boliviana（鞘翅目：Chrysomelidae）是美利坚合众国（美国）批准的S. viarum生物防治剂。尽管G. boliviana的宿主特异性已在美国进行了广泛的测试，但还进行了额外的无选择测试以确定甲虫是否具有足够的宿主特异性以在澳大利亚释放。主机测试列表包括Solanum原产于澳大利亚的物种，以及之前已测试过的重要农业物种。成虫和幼虫无选择测试均表明G. boliviana在目标杂草S. viarum和测试中包括的其他植物物种中表现不佳。除了目标杂草外，仅在两种植物上观察到产卵，S. viarum产卵明显更多（19.5 ± 0.4 个卵/株），其次是S. brownii（2 ± 0.4 个卵/株）和S. melongena（1.8 ± 1.5 个鸡蛋/植物）。产在S. viarum上的卵 90%发育成成虫，而产在S. melongena上的卵只有 1 个完成发育。幼虫无选择馈送评估表明，幼虫成活和发育是最高上S. viarum随后（80％）S.野百合（30％）和S.茄子（20％）和对一较小程度S. lithophilum（ 2.5%）。我们的结果有助于评估G. boliviana饲养和发育对澳大利亚本土或农业上重要的茄属物种的潜在脱靶效应的风险。